A long-held ambition for many educators and assessment experts has been to integrate summative and formative assessments so that data from external assessments used for system monitoring may also be used to shape teaching and learning in classrooms. In turn, classroom-based assessments may provide valuable data for decision makers at school and system levels. Currently there are important technical barriers to this kind of seamless integration. Nevertheless there are a number of promising developments in the field. Ongoing research and development aims at improving testing and measurement technologies, as well strengthening classroom-based formative assessment practices. Improved integration of formative and summative assessment will require investments in new testing technologies, teacher training and professional development, and further research and development.